The latest version of Skype for Mac allows you to chat directly with your Facebook friends, hopefully bringing you a better user experience than other chat system. It also allows you to see your wall and your friends.
I wish this happened more often, because I'm tired of having to deal with so many ways to communicate with my friends and family. Imagine a world in which every single instant messaging, voice and visual communication system operated between each other, regardless of the company who owns the system. Or imagine the same in reverse: a world where you couldn't call someone's cellphone because they were in a different network. This is stupid.